To Do long water fast during college days

Hello im 20years old weighting 80kgs Im looking to do Water Fast more than 10days and less than 20 To Be safe ive only done 2 one day Water Fasts till now i just wanted to know a couple of things
1) ive the will power to get through 2nd day and 3rd i know its very hard but i can but will i have energy to study after the initial 2days (college closes for 1week after 2 days so i want to study at home)
2) what if any risks are there and if recommended to see a doctor who should i see imean a doctor specialised in which area of medicines(like ENT , ORTHO)
3)will it cure my allergic sneezing and the headaches(seen few doctors didnt help at all)
4) and even if i lose weight how to keep it off after the fast
5)ending the fast easing back In To eating (assume the fast is for maybe 10-15 days)
6) when to stop fasting return of hunger? Or any other symptoms to look out for other than detox symptoms
7) any other information thatll will help me be safe will be a lot helpfull
-please help me guys i know this forum has lot of experienced persons feel free to give me info even if itisnt related to the above questions im waiting this is my first post (im not a native english speaker so sorry if theres any mistake 😊)